SPC365

Incremental prognostic value of CT-derived extracellular volume in severe aortic stenosis

Session: SESSÃO DE COMUNICAÇÕES ORAIS 14 - PRÉMIO JOVEM INVESTIGADOR (CLÍNICA E BÁSICA)
Speaker: Rita Almeida Carvalho

Congress: CPC 2025
Topic: B. Imaging
Theme: 03. Imaging
Subtheme: 03.2 Computed Tomography
Session Type: Comunicações Orais
FP Number: ---
Authors: Rita Almeida Carvalho; Márcia Presume; Rita Reis Santos; Francisco Albuquerque; Pedro Lopes; Francisco Gama; Cláudia Silva; Pedro Freitas; Sara Guerreiro; João Abecasis; Rui Campante Teles; António Ferreira

<p><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif"><strong>Background</strong>: </span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">Severe aortic stenosis (AS) has a poor prognosis without timely intervention. While risk stratification is primarily guided by clinical scores, myocardial extracellular volume estimation using cardiac computed tomography (ECV-CT), a marker of fibrosis, has emerged as a promising prognostic tool. This study sought to determine if ECV-CT can provide independent and incremental prognostic information to established clinical risk markers. </span></span></p>

<p><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif"><strong>Methods</strong>:</span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">This prospective single-center study included consecutive patients with severe symptomatic AS undergoing pre-TAVR (transcatheter aortic valve replacement) CT. Patients with prosthetic aortic valves or known cardiac amyloidosis were excluded. Imaging was performed using a 192-slice dual-source CT scanner, with ECV-CT obtained via an additional post-contrast, low-radiation-dose, prospective acquisition (Figure 1A). ECV-CT values were compared with two risk scores: EuroSCORE II and PRIORiTize-TAVI. The composite endpoint was time to all-cause mortality or cardiovascular hospitalization.</span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif"><strong>Results</strong>:</span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">A total of 316 patients (mean age 81 &plusmn; 8 years; 44% male; mean transaortic gradient 50 &plusmn; 15 mmHg; mean aortic valve area 0.74 &plusmn; 0.19 cm&sup2;; mean left ventricular ejection fraction 56 &plusmn; 11%) were analyzed. The median ECV-CT was 33.9% (IQR 29.5-38.7). Over a median follow-up of 340 days (IQR 198&ndash;517), the composite endpoint occurred in 72 patients (23%), including 47 deaths (15%) and 25 cardiovascular hospitalizations (8%). Patients reaching the endpoint were older (84 &plusmn; 8 vs. 80 &plusmn; 8 years, p=0.012), had lower LV ejection fraction (51 &plusmn; 13 vs. 57 &plusmn; 10%, p&lt;0.001), higher NT-proBNP levels (4002 pg/mL (IQR 929-8678) vs. 838 (IQR 377-2126), p&lt;0.001), and higher scores on both EuroSCORE II (6.32 &plusmn; 5.12 vs. 4.05 &plusmn; 3.23%, p=0.002) and PRIORiTize (4.4 &plusmn; 1.6 vs. 3.3 &plusmn; 1.3, p=0.008). These patients also had higher median ECV-CT values (39.8% (IQR 33.5-44.2) vs. 32.9% (IQR 29.5-38.3), p=0.001). </span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">Decision tree analysis identified an ECV-CT value &ge;40.2% as the best threshold for predicting outcomes (Figure 1B). Patients with ECV-CT &ge;40.2% (n=53) accounted for 17% of the study population but were responsible for 29% of all events. </span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">Multivariate Cox regression showed that logECV-CT remained an independent predictor of the composite endpoint after adjusting for EuroSCORE II (HR 4.2, 95%CI 1.3-13.9, p=0.016) and PRIORiTize (HR 3.9, 95% CI 1.3-11.6, p=0.012). Finally, nested regression models of the global Chi-square value of the likelihood ratio test demonstrated that incorporating logECV-CT significantly improved the predictive performance of both EuroSCORE II and PRIORiTize (Figure 1C). </span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif"><strong>Conclusion</strong>: </span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">CT-derived ECV provides incremental prognostic value beyond clinical scoring systems in patients with severe AS, aiding in identifying higher-risk patients. The potential role of this marker for clinical decision-making warrants further investigation. </span></span></p>